Skid steer loaders are highly maneuverable compact machines used in a variety of applications ranging from asphalt milling to earth moving, depending on the job and type of attachment being used. For applications requiring reduced ground pressure or increased fraction, tracked skid steer loaders have been developed. These tracked skid steer loaders, such as compact track loaders and multi-terrain loaders, have rubber-tracked undercarriages that support a machine frame and transfer the powertrain and implement forces to the ground. Typical compact track loaders, which have a rubber over steel track, use a rigid mounting from the undercarriage to the machine frame. While this rigid mounting allows for an efficient transfer of machine power to the implement, it results in an uncomfortable ride for the operator and a reduction in machine performance when the tracks do not maintain full contact with the ground.
Multi-terrain loaders, which use a solid rubber track, have been developed with suspension systems. For example, U.S. Pat. No. 6,435,291 to Lemke et al., entitled Suspension and Drive Mechanism for Multi-Surface Vehicle, (“Lemke”), discloses a tracked vehicle that produces a reduced ground pressure for traveling over soft ground surfaces without damaging the surface. The disclosed track vehicle uses an undercarriage having torsion axles arranged in a five-bar linkage with the machine frame.
While this configuration may work adequately for applications seeking a reduced ground pressure, the five-bar linkage suspension disclosed in Lemke may not be suitable for applications requiring an efficient transfer of machine power to the implement, such as grading.